touraj sabzevari; Ali Talebi
Abstract
In many civil engineering projects such as urbanization, road and dam construction, before designing and operating, the subject of landslide of the hillslopes, especially in the conditions of high rainfall, which may have financial and human damages, should be considered. TOPMODEL is a subsurface model ...
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In many civil engineering projects such as urbanization, road and dam construction, before designing and operating, the subject of landslide of the hillslopes, especially in the conditions of high rainfall, which may have financial and human damages, should be considered. TOPMODEL is a subsurface model used to estimate surface and subsurface runoff of watersheds based on the Dunny-Block mechanism. This model is capable of detecting catchment saturation area and estimating the soil moisture deficit (SMD) across catchment. There is a relation between the hillslope saturation index, which is a key parameter in landslide models, and SMD. In this study, the relationship between the two models of SINMAP (landslide model) and TOPMODEL and their parameters have been studied. For this purpose, the data of the ILAM Dam catchment data located in the southeastern province of ILAM in IRAN was used. The ten hillslopes of the area were taken to calculate the sliding. Using GIS, maps of SMD and index of saturation were calculated based on TOPMODEL, and finally, stability maps of SINMAP were calculated for the region. Hillslopes 3, 4, and 5 are quasi-stable according to the model, stability probability is less than 50% and stability probability is more than 50%, and in nature these hillslopes are unstable. The 8, 9, and 10 hillslopes that are used in nature from the vegetation of oak trees are stable, according to the model of these three hillslopes.
Ali Talebi; Zahra Eslami; Abdolhossein Abbasi
Abstract
Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. ...
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Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. Also, the priorities of sub-basins were studied using flooding coefficient and peak discharge per unit area experimental methods. In order to run HEC-HMS model, plan rainfall with two, five, 10 and 50 years return periods were used. Flood hydrographs associated with each precipitation were calculated for each sub-basin, using the sequential removal method of sub-basins and removing CN in each sub-basin in each run of the model and their effect were computed in flood generation. Results showed that sub-basin I has the first priority is flooding potential, considering independent and depended sub-basins. Prioritization of sub-basins with two experimental methods had different results that are independent from a particular process. As E sub-basin had sixth priority in flooding coefficient method and third priority in the peak discharge estimating method. By comparing the prioritization of sub-basins in HEC-HMS model in different return periods, results showed that sub-basins prioritization in different return periods has specific process. Therefore, HEC-HMS model is more efficient compared to experimental methods in sub-basins prioritization in flooding.
Arash Zare Garizi; Ali Talebi; Monireh Faramarzi
Abstract
In this study, SWAT model was used for simulating soil erosion and sediment transport in Gharesou Watershed, Golestan Province and for identifying and prioritizing critical areas of soil erosion. After model calibration, validation and uncertainty analysis using semi-automatic SUFI-2 method, the outputs ...
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In this study, SWAT model was used for simulating soil erosion and sediment transport in Gharesou Watershed, Golestan Province and for identifying and prioritizing critical areas of soil erosion. After model calibration, validation and uncertainty analysis using semi-automatic SUFI-2 method, the outputs of the calibrated model were used for assessing spatial pattern of soil erosion and sediment. For this purpose, four indices including: load per unit area index, concentration index, load index and total index were defined and analyzed based on the model outputs. The results indicated that, despite lack and uncertainty of available data, SWAT model performance in simulating soil erosion and sediment transport in Gharesou watershed is quite acceptable. During calibration, the simulated monthly sediment loads matched the observed values with a Nash-Sutcliffe coefficient of 0.24 and PBIAS of -17%. The values for validation period were 0.2 and -12.1% respectively, indicating the model’s weakness in simulating sediment dynamics and its capability in predicting average sediment load. Assessing spatial pattern of erosion and sediment indices showed that, in general, critical sub-watersheds based on load per unit area index are located in upstream areas of watershed while sensitive sub-watersheds in terms of sediment concentration are situated in the middle part of the watershed, and sensitive sub-watersheds with respect to sediment load are in downstream. Suitable conservation practices were recommended for each zone based on their ecohydrological conditions. The outputs of this study can help experts and managers in planning of management practices for the watershed.
